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LCROSS Team Changes Target Crater For Impact

Posted by kdawson on from the illuminated-ejecta dept.

Matt_dk sends word that NASA has chosen a new target crater into which to crash the Lunar Crater Observation and Sensing Satellite (LCROSS) mission vehicles. "The decision means that when NASA's LCROSS probe and its spent Centaur rocket stage slam into the moon on Oct. 9, they will crash into the large crater Cabeus, and not the nearby (and smaller) Cabeus A crater that was previously targeted. ... The data suggests the new target Cabeus has a concentration of hydrogen — an indication of possible water ice — that's higher than anywhere else at the lunar south pole. ... A small valley etched into the otherwise tall crater ridge of Cabeus should allow sunlight to shine on the ejecta cloud kicked up when LCROSS and its Centaur rocket stage crash into the moon in successive impacts."

39 comments

  1. Why not remotely? by BadAnalogyGuy · · Score: 3, Interesting

    We have the technology to analyze the spectrography of astral bodies. We can even detect the composition of stars many light years away from the Earth.

    Why do we need to clutter up the Moon with these "crash landing" sensors? At least it would make sense to have sensor devices that could be actively mobile and roam the surface after landing.

    Yes, it would be expensive, but if we're going to be doing something we should try to get the longest life out of it possible.

    1. Re:Why not remotely? by solafide · · Score: 5, Informative
      It's hard to dig deep into rocks without some variety of explosive. It's pretty hard to plant explosives well. The Mars rovers have a rock-digging tool, the RAT: it regularly measures its dig depths in millimeters. This project wants to dig in and learn about well below the surface: we don't really have a good way of doing this right now without smashing stuff.

      We can always recycle this variety of space junk once we get there: this is patently untrue of genuine junk in space. The usefulness of a ridiculously high-tech junkyard cannot be underestimated.

    2. Re:Why not remotely? by wizardforce · · Score: 4, Informative

      We can even detect the composition of stars many light years away from the Earth.

      spectral lines from a gas are easy to identify as we only need to match the lines to the lines characteristic of various elements. Solid bodies like the moon are different. You can't just take a look at the light reflected off the moon and know whether there is water there. You can use cosmic radiation generated neutrons to probe the moon's composition but it only tells you what elements are in the soil, not the chemical form they are in. If we were to slam a probe into a section of the moon where we think there's water, the impact could vaporize some water fro mthe regolith if there is any which gives us a higher chance of detecting gaseous water spectrographically. Granted it would be easier still for us to send a probe to the surface and take some actual samples of these areas but when you've got a probe in the area that isn't really doing much else useful, you may as well get your money worth by using it in this fashion.

      --
      Sigs are too short to say anything truly profound so read the above post instead.
    3. Re:Why not remotely? by compro01 · · Score: 3, Informative

      We cannot spectroscopy through the moon's surface.

      That's why we're throwing a heavy object at it so we can see the stuff we're wanting to look at.

      What is crashing into the moon is the spent rocket. The sensors are on the orbiter which will fly through the plume created by that impact. To go through that, it needs to get very close to the surface and there's no way to recover that, so it crashes shortly afterwards.

      Also, rovers would not cut it for this. You would either need heavy digging equipment (Which is far too large/heavy to be feasibly boosted into space with current techniques) or (literally) a ton of TNT.

      As for cluttering, this is just another meteor impact among thousands of others, aside from that we're aiming this one for an area we're interested in examining.

      --
      upon the advice of my lawyer, i have no sig at this time
    4. Re:Why not remotely? by Shag · · Score: 1

      Stars emit their own light; the moon doesn't. We have a good idea of what's on the surface (from spectroscopy, and of course sample-return missions) but we want to know what lies a little bit beneath it, so we're trying to kick up some dust.

      Same approach that NASA's "Deep Impact" mission took in 2005. I got to see that one, but LCROSS is scheduled during my days off... makes me a sad, forlorn telescope operator. ;) Maybe I can go volunteer that night and try to get a look at it through a 16-inch or something.

      --
      Village idiot in some extremely smart villages.
    5. Re:Why not remotely? by DMUTPeregrine · · Score: 2, Insightful

      It's easier to get data about what's deep under the surface by blowing that stuff up so it lands on top than it is to build a digging machine. The machine has to carry a big battery, drill, etc, while the impactor just has to hit hard. Given orbital velocities, hitting hard is very easy.

      --
      Not a sentence!
    6. Re:Why not remotely? by macshit · · Score: 1

      Same approach that NASA's "Deep Impact" mission took in 2005. I got to see that one ...

      Er, so what did it look like...?

      --
      We live, as we dream -- alone....
    7. Re:Why not remotely? by Shag · · Score: 2, Interesting

      The target became a lot more visible at impact, due to a bunch of dust being kicked up (and reflecting sunlight).

      The moon (around last quarter) will not particularly become more visible since it's a much bigger target than any dust cloud LCROSS might kick up - but maybe scoeps looking at the right part will see something.

      --
      Village idiot in some extremely smart villages.
    8. Re:Why not remotely? by plastbox · · Score: 2, Funny

      I r in ur lab obseervin ur scoeps, k thx bai!

    9. Re:Why not remotely? by smaddox · · Score: 1

      It's hard to dig deep into rocks without some variety of explosive. It's pretty hard to plant explosives well. The Mars rovers have a rock-digging tool, the RAT: it regularly measures its dig depths in millimeters. This project wants to dig in and learn about well below the surface: we don't really have a good way of doing this right now without smashing stuff.

      We can always recycle this variety of space junk once we get there: this is patently untrue of genuine junk in space. The usefulness of a ridiculously high-tech junkyard cannot be underestimated.

      Exactly. Furthermore, why bother planning and executing a difficult controlled landing when all that kinetic energy could be used directly for 'drilling' into the rock.

    10. Re:Why not remotely? by RabidMoose · · Score: 1

      You would either need heavy digging equipment (Which is far too large/heavy to be feasibly boosted into space with current techniques) or (literally) a ton of TNT.

      Don't forget about Bruce Willis. You won't get far without him, and he's likely been putting on weight. Need to figure that into the cost.

    11. Re:Why not remotely? by Anpheus · · Score: 1

      I for one welcome our new alien paleontologist overlords and their "history probes."

    12. Re:Why not remotely? by RockDoctor · · Score: 1

      It's hard to dig deep into rocks without some variety of explosive. It's pretty hard to plant explosives well.

      Not untrue.

      The Mars rovers have a rock-digging tool, the RAT: it regularly measures its dig depths in millimeters.

      The RAT stands for "Rock Abrasion Tool" ; it's purpose is more like a geologist's hammer than a miner's shovel. They want it to abrade enough material off the surface to remove any weathering patina. As a side effect of achieving this, the tool also leaves a flat surface, and can abrade several millimetres for "serial sectioning". An additional purpose of the tool is to allow the other rover probes to examine the mineralogy of the rocks examined.
      As a geologist, I use my hammer much more for exposing a fresh surface of a rock than I do for excavating. Then I get out the hand lens and examine the fresh (and weathered) surface. The analogy is pretty close. I do occasionally use the hammer for grubbing a rock out of the ground, but the tool isn't very good for that.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  2. Yay more space junk. by yourassOA · · Score: 0

    Like earth doesn't have enough crap on it, lets send some to the moon. We need lunar littering laws. Who will clean up the mess?

    1. Re:Yay more space junk. by JustOK · · Score: 1

      Mayor McCheese.

      --
      rewriting history since 2109
    2. Re:Yay more space junk. by KlaymenDK · · Score: 0, Redundant

      Exactly.

      Ed: Hey you guys, we think we found water! Real, useful, drinkable water (ice...)!
      Joe: Quick, let's go contaminate it with rocket wreckage!
      Crowd: Yaaaay!

      --
      "Good news, everyone!"
  3. Not too bad by wesslen · · Score: 2

    I can barely hit my friends with nerf guns. If NASA only misses its target (which is about 238,857 miles away from here) by the next nearest crater I raise my glass to you NASA. Not too bad NASA, not too bad...

  4. Well... by Capsy · · Score: 0

    Or when the rocket impacts, it destroys the moon, and Earth gets messed up real bad by moon pebbles. Maybe there's aliens inside the moon? Something akin to the creamy center of a Twinkie.

    --
    "Chance favors only the prepared mind." -Archimedes
  5. Attention, Tinfoil Hat Wearers by hyades1 · · Score: 4, Funny

    No doubt the alternate target was chosen in order to destroy evidence of alien ruins before improved telescope technology falls into the hands of average people. Hey, a guy just got a picture of the space station and shuttle from his back yard, right? That's almost as far away as the moon, isn't it?

    --
    I've calculated my velocity with such exquisite precision that I have no idea where I am.
    1. Re:Attention, Tinfoil Hat Wearers by wesslen · · Score: 2

      I'm pretty sure that's sarcastic but here's the numbers anyway:

      moon to earth = 238,857 miles

      ISS to earth = 220 miles

      the moon is over 1000 times farther than the ISS

      Hooray applied mathematics!

    2. Re:Attention, Tinfoil Hat Wearers by siddesu · · Score: 2, Funny

      Not really, the aliens removed all their shit in the late 50s. Besides, theirs was on the dark side of the moon, they used periscopes protruding across the terminator to watch us.

      The current project's goal is more modest -- is to blow up the alleged "moon landing" sites. That is how they will explain to us why there are no astronaut footprints. They will look at you and seriously say "Our subsequent moon research projects covered up the tracks".

    3. Re:Attention, Tinfoil Hat Wearers by Higgs_Bozon · · Score: 1

      Yeah, right!
      Do you actually BELIEVE this crap that they told you in school?
      Looks again like it's
      Aliens: 1 - - schoolboy math-wizard: 0

      (sigh....) When WILL you learn?

      --

      -
      Extracting sunbeams from /. Bozons since 1766
  6. Google Maps of Cabeus crater by BadAnalogyGuy · · Score: 5, Informative

    http://maps.google.com/moon/#lat=-83.215692&lon=-38.320312&map=visible&apollo=&q=Cabeus

  7. *had* water? by Anonymous Coward · · Score: 0

    > the new target Cabeus has a concentration of hydrogen -- an indication of possible water ice

    Or at least, it *had* until we smashed a probe into it at high speed and distributed the only concentration of ice on the moon over ten thousand square kilometers of area.

    1. Re:*had* water? by JustOK · · Score: 1

      As sentient moonicans look up and scream in horror in the few remaining moonminutes they have left.

      --
      rewriting history since 2109
  8. Forty years ago they could land stuff by physburn · · Score: 0
    Forty years ago they could land stuff on the moon. Now apparately, the best NASA could do is crash probes, and look at the ejector. Surely what they really need is a lunar rovers, complete with drills, robot arms, and a on board mineralogy lab. If NASA could manage that for Mars they should be able to manage it for the moon.

    ---

    Astronomy Feed @ Feed Distiller

    1. Re:Forty years ago they could land stuff by QuantumG · · Score: 1

      If NASA could manage to secure funding for that for Mars they should be able to manage it for the moon.

      There ya go, fixed that for ya.

      --
      How we know is more important than what we know.
    2. Re:Forty years ago they could land stuff by Anonymous Coward · · Score: 0

      They look at the ejecta. I doubt a probe destined to crash, with no people on board has ejectors of any kind.

    3. Re:Forty years ago they could land stuff by confused+one · · Score: 3, Interesting

      There coming. The LCROSS mission is a pre-cursor quick turn mission. The results will be used in the decision process for where to place the rovers.

    4. Re:Forty years ago they could land stuff by Anonymous Coward · · Score: 0

      They look at the ejaculate? Yuck!

    5. Re:Forty years ago they could land stuff by smoker2 · · Score: 1

      The word is ejecta and you obviously have no idea what's involved here.

  9. Smash... by tweewo · · Score: 1

    OMG... Cheese!

  10. Orbiter simulation by Amiralul · · Score: 2, Informative

    Here's a simulation of the impact, done with Orbiter software and a bunch of plugins: http://www.youtube.com/watch?v=mXTc47x4HDk

  11. Wait a minute... that's _MY_ crater! by jamesh · · Score: 2, Funny

    They can't do that. I purchased that crater over the internet. I paid good money for it and I have the deed to prove it.

  12. Pessimistic Outlook by organgtool · · Score: 1

    Wow, that doesn't sound like an optimistic outlook for a smooth landing of their craft.

    It reminds me of a line I like to use on women: Baby, by the third date I'll be thoroughly disappointing you in bed.

    1. Re:Pessimistic Outlook by PeterBrett · · Score: 1

      Wow, that doesn't sound like an optimistic outlook for a smooth landing of their craft.

      If you'd RTFA (yeah, new here, etc) you'd know that the whole point of their craft is to thump into the moon as hard as possible. A smooth landing would be a mission failure.

      --
      Pirate Party UK
  13. All These Planets Are Yours Except Europa. by mmell · · Score: 1
    Attempt No Landing There.

    Use them well.

    Use them in peace.

  14. Re:Still too much money by Kagura · · Score: 2, Funny

    We've done these kinds of "impact" missions on Mars several times, generating a large dust cloud each time. The only difference is this time something will be watching/analyzing the dust cloud.......... ;)